[Mesa-dev] Bugs in fbo-sys-blit (problems with fake front and missing invalidates)

[Ville Syrjälä]

On Wed, May 29, 2013 at 01:39:00PM -0700, Paul Berry wrote:
> I started this discussion with just some of the Intel folks, and Eric
> suggested I bring it to the mesa-dev list.
> 
> The short version is: in my efforts to implement fast color clears on Intel
> hardware, I've uncovered some problems with the fbo-sys-blit piglit test,
> which I've traced to 3 bugs.  I could use some help with bug (2) below,
> which I suspect is a bug in the X server.
> 
> ---------- Forwarded message (footnotes added) ----------
> 
> First of all, a brief summary of what fbo-sys-blit's piglit_display() does:
> 
> a. Clear the back buffer to green.
> b. Copy the back buffer to the front buffer using a blit.
> c. Clear the back buffer to red.
> d. Read the contents of the front buffer to verify that it's green.
> 
> I've found three bugs:
<snip>

Did you try this [1] patch from Chris? I had a similar patch in a
private tree way back when, but for some reason I decided that it's not
necessary, and hence didn't send it out. I can't actually recall why I
came to that conclusion, nor can I think of a good reason now either.
But it's been quite a while since I poked at any dri2 or composite stuff
so I may be out of practice.

[1] http://patchwork.freedesktop.org/patch/12111/

-- 
Ville Syrjälä
syrjala at sci.fi
http://www.sci.fi/~syrjala/